Methods for Estimating Modal Bandwidth Spectral Dependence

Abstract

Methods for estimating the Effective Modal Bandwidth (EMB) of laser optimized Multimode Fiber (MMF) at a specified wavelength, λS, based on the measured EMB at a first reference measurement wavelength, λM. In these methods the Differential Mode Delay (DMD) of a MMF is measured and the Effective Modal Bandwidth (EMB) is computed at a first measurement wavelength. By extracting signal features such as centroids, peak power, pulse widths, and skews, as described in this disclosure, the EMB can be estimated at a second specified wavelength with different degrees of accuracy. The first method estimates the EMB at the second specified wavelength based on measurements at the reference wavelength. The second method predicts if the EMB at the second specified wavelength is equal or greater than a specified bandwidth limit.

Description

CROSS REFERENCES TO RELATED APPLICATIONS[0001]This application is a continuation of U.S. patent application Ser. No. 16 / 341,536, filed Apr. 12, 2019, which claims priority to International Patent Application Serial No. PCT / US2017 / 055307, filed Oct. 5, 2017 and U.S. Provisional Application No. 62 / 407,695, filed Oct. 13, 2016, the subject matter of which is hereby incorporated by reference in its entirety.BACKGROUND OF THE INVENTION[0002]The present invention relates in general to the field of optical fibers and more specifically, to multimode fibers (MMF) designed for operation at multiple wavelengths. The present invention also relates to the field of modeling, designing, production, sorting and testing of MMFs. More specifically it relates to the estimation of the MMF EMB at multiple wavelengths.[0003]The invention is also related to modal and chromatic dispersion compensation in Vertical Cavity Surface Emitting Laser (VCSEL) based MMF channels [1]. The methods described here can p...

AI Technical Summary

Benefits of technology

This patent is about methods for estimating the bandwidth of a laser optimized multimode fiber at different wavelengths. The methods involve measuring the delay of signals in the fiber and using these measurements to compute the effective bandwidth at a reference wavelength. These methods can provide reasonably accurate estimates of the bandwidth at different wavelengths, and can also predict if the bandwidth at a specific wavelength is equal or greater than a specified limit. Overall, this patent describes methods for accurately estimating the bandwidth of multimode fibers, which can be useful for designing optical communication systems.

Problems solved by technology

Due to the test complexity, it is time consuming and the equipment required to perform the test is expensive; EMB test requirements for multiple wavelengths will significantly increase testing time and consequently, increase fiber cost.

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